1. Field
One or more embodiments relate to a deionization apparatus to regenerate an electrode using vibration and a method of controlling the same.
2. Description of the Related Art
Water and, more particularly, subterranean water, contains large amounts of minerals such as calcium, magnesium and so on. The concentration of calcium or magnesium is called hardness, water having a high mineral concentration is called hard water, and water having a relatively low mineral concentration is called soft water.
If hard water, that is, water having high hardness, is used in electric home appliances such as a washing machine or a dish washer, the water reacts with a detergent and thus detergency is deteriorated. A large amount of scales accumulate on a channel in which the water flows, and thus product reliability is deteriorated.
Accordingly, conventionally, a soft water machine using ion exchange resin was suggested.
The soft water machine using the ion exchange resin softens water by exchanging Ca2+ and Mg2+ ions of hard water components included in water with Na+ of NaCl injected into the ion exchange resin. In the soft water machine using the ion exchange resin, NaCl is periodically injected, and the ion exchange resin is replaced with a new one due to impurities contained in the water. In addition, the method using the ion exchange resin is uneconomical, because an acidic or basic solution is used when the resin is regenerated and a large amount of polymer resin and chemicals are used in order to treat a large amount of water.
Therefore, recently, research into capacitive deionization (hereinafter, referred to as CDI) has been actively conducted.
A CDI technique is based on a simple principle that power is applied to two porous electrodes such that negative ions are electrically absorbed to a positive electrode and positive ions are electrically absorbed to a negative electrode so as to eliminate ions dissolved in a fluid such as water. In addition, when the electrodes are saturated with absorbed ions, the polarities of the electrodes are reversed or the power is turned off so as to separate (desorb) the ions absorbed to the electrodes. Therefore, the regeneration of the electrodes is simply performed. In addition, in the CDI technique, since a cleaning solution such as an acidic or basic solution is not used for the regeneration of the electrodes unlike the method using the ion exchange resin or a reverse osmosis method, secondary chemical waste is not generated and the electrodes are hardly corroded or contaminated. In addition, lifespan is semi-permanent, energy efficiency is higher than other methods, and energy consumption may be reduced 10 to 20 fold.